A New Environmentally Friendly Clay Stabilizer

Abstract

Summary Clay stabilizers are used to prevent fines migration and clay swelling, which are caused by the contact of clays with low salinity or high pH fluids. Previously used clay stabilizers, including hydroxy-aluminum, zirconium oxychloride solutions, and cationic polymers have several drawbacks. Hydroxy-aluminum and zirconium oxychloride solutions can be leached by acids (Coppel et al. 1973). Cationic organic polymers can cause formation damage in some cases (Nasr-El-Din et al. 1999). Their environmental impact is also questionable (Patel 2009). There is a need to develop new clay stabilizers that can work with acid treatments and that are environmentally acceptable. Laboratory studies were conducted on a newly developed inorganic aluminum/zirconium-based compound. Coreflood experiments were conducted on Berea sandstone cores (1.5 in. in diameter, 6 and 20 in. in length) to assess the effectiveness of the new compound at high temperatures and determine the impact of acids on its performance. Inductively coupled plasma was used to measure the concentrations of aluminum and zirconium in the coreflood effluent samples. The new clay stabilizer was very effective in mitigating fines migration. Experimental results showed that unlike previous Al/Zr compounds, the new stabilizer was effective even after using several 15 wt% HCl acid washes. In addition, it did not cause formation damage, and worked very well up to 300°F. It is non-toxic, with no smell, and environmentally friendly.